PROJECT SUMMARY The primary risk factor for prevalent diseases including cancer and neurodegeneration is aging. Despite an extensive list of age-associated defects, we have a limited view of how aging becomes a major disease determinant. The traditional method in the field is to induce genetic modifications in a model organism before the aging process manifests itself, and to subsequently determine how these alterations affect lifespan. These studies have been instrumental in identifying factors that impact longevity. However, they lack the temporal resolution to distinguish the gene products that directly counteract age-associated damage from those that have indirect effects on lifespan, merely through delaying cell cycle progression, growth and/or development. The key challenge in the aging field is the development of an effective approach that allows identification of the underlying mechanisms of aging and manipulation of identified factors in a controlled manner. Here, I propose an innovative strategy designed to identify genes that directly rescue age-induced dysfunction. My approach is to use the natural system of gametogenesis, which I have shown can naturally reverse cellular aging, as a platform to illuminate the molecular causes of aging and to ultimately develop new strategies to counteract age-induced cellular damage. Gametogenesis is a tightly regulated developmental program whereby a progenitor cell undergoes cell division and differentiation to form haploid gametes; the mature germ cells necessary for the propagation of sexually- reproducing organisms. I discovered that in budding yeast, old cells reset their lifespan and remove age- induced cellular damage upon gametogenesis. Furthermore, I found that the expression of a gametogenesis- specific transcription factor, NDT80, during vegetative growth extends the lifespan of old cells. This finding indicates that aging can be rescued directly, and that the factors necessary for age-reversal during gametogenesis have the ability to function in other cellular contexts. Based on this logic, my lab will identify rejuvenation factors by performing a high-throughput screen, designed to identify anti-aging factors whose expression in old cells cause rescue of cellular aging and life span extension. The subsequent functional characterization of these genes using microfluidics, high-resolution live-cell microscopy and biochemical approaches will delineate their mode of action, thereby allowing us to paint a system-wide view of the underlying principles of aging. In parallel, I propose experiments to unravel the cellular quality-control pathways essential for remodeling of gametes, and the utilization of these pathways to eliminate age-induced cellular damage in somatic cells. Our studies will provide insights into the molecular basis of aging and should stimulate the development of novel strategies to decrease susceptibility to age-associated disease and extend health span.